Fluid operated device



Feb. 28, 1967 J. E. GORDON 3,306,171

FLUID OPERATED DEVICE Filed May 11, 1964 2 Sheets-Sheet 1 INVENTOR.

JOHN E. GORDON his ATTORNEY Feb. 28, 1967 J. E. GORDON 3,306,171

FLUID OPERATED DEVICE Filed May 11, 1964 2 Sheets-Sheet 2 INVENTOR.

JOHN E. GORDON BY %M his ATTORNEY United States Patent 3,306,171 FLUIDOPERATED DEVICE John Edward Gordon, Gait, Ontario, Canada, assignor toJoy Manufacturing Company, Pittsburgh, Pa., a corporation ofPennsylvania Filed May 11, 1964, Ser. No. 366,365 7 Claims. (Cl. 91-180)This invention relates to a fluid operated device and more particularlyto a compressed gas operated motor having an improved rotary inlet andexhaust valve.

Compressed air motors of the multi-cylinder type having a unitary valvestructure capable of providing timed inlet of compressed air to theindividual cylinders and permitting exhaust air to flow from theindividual cylinders are well known in the art. It is further well knownthat for efiicient high speed operation an inlet port of relativelysmall angular dimension should be provided in the rotary valve so thatthe cut ofi of the inlet air occurs while the piston is somewhere in middownstroke, allowing expansion of the air with consequent reduction inpressure as the piston continues its downward stroke. Thus, when thecylinder is opened to the surrounding atmosphere by action of the valvein providing the exhaust connection, a minimum amount of the energy ofthe compressed air is lost in the exhaust system. It is further wellknown that for high torque in low speed operation the inlet port of therotary valve should be very much larger in angular dimension than theoptimum size for efficient high speed operation as hereinabovedescribed. It therefore follows that the angular size of the inlet portof the rotary valve for a compressed air motor, required to operate at avariety of speeds, is a compromise between the demands for a large portgiving adequate slow speed torque and a small port giving high speedefiiciency, with neither demand being fully satisfied.

Another limitation on the minimum angular size of inlet ports, that canbe used in devices of the prior art, arises from the necessity of havinga portion of the port open to a suitable cylinder for starting the motorfrom whatever position it was in when it was stopped. As a result ofthis latter requirement even those air motors which were designed onlyfor high speed operation could not be provided with the desirably smallinlet port which would give maximum high speed efiiciency.

In the rotary valve of the present invention the angular size of themain inlet port (30-35) is largely determined by the desired cut ofi"point in the downstroke of the piston operating at high speed and issized so that after cut oif a suitable amount of compressed airexpansion takes place so that when the exhaust port is opened a minimumof energy is left in the compressed air to be lost in the exhaustsystem. The rotary valve of this invention in addition to the main inletport is provided with a series of much smaller inlet ports or orificesthrough which compressed air can be supplied to the cylinders at a ratemuch less rapid than the supplying of air through the main port. Theseauxiliary ports are positioned in the valve so that they do notcommunicate with the cylinders until after the main port has nearly orcompletely closed and might be characterized as trailing auxiliaryports. These auxiliary ports are orifices of a suitable size so that athigh speed operation of the air motor to which this rotary valve isapplied the orifice effect ensures that there is time for very littleair to flow through the auxiliary ports with the result that the airmotor using the rotary valve of this invention operates as though it hadonly a relatively small main port and consequently has very good highspeed operating etficiency because it utilizes the expansive energy ofthe compressed air.

For starting the air motor using the rotary valve of 3,306,171 PatentedFeb. 28, 1967 ice this invention one or more of the auxiliary ports willalways be open to a suitable cylinder wherein the piston has partiallycompleted a downstroke so that air for starting the motor is supplied toa suitable piston to begin rotation of the crankshaft bringing otherpistons into position to continue the action. For slow speed operationthe auxiliary ports are open for a length of time great enough to allowfor maintaining the pressure within the cylinder a greater length oftime with resulting greater means eifective pressure than would bepossible with a single inlet port of the angular size hereinabovedescribed. Therefore, an air motor using the rotary valve of thisinvention has good low speed torque characteristic, satisfactorystarting from any stopped position and furthermore has better high speedoperating efficiency than similar motors of the prior art.

It is therefore an object of this invention to provide a new andimproved compressed gas motor having a novel rotary valve mechanism.

It is another object of this invention to provide a new and improvedcompressed gas motor having good high speed operating eificiency andalso having good low speed torque characteristics and starting abilityfrom any stopped position.

It is a more specific object of this invention to provide a new andimproved rotary valve for a multi-cylinder compressed air motor whereinthe rotary valve is provided with a large exhaust port, main inlet portand a plurality of trailing auxiliary inlet ports much smaller than themain inlet port.

It is a further specific object of this invention to provide a new andimproved compressed gas motor having a rotary valve provided with aplurality of circumferentially spaced inlet ports of different sizeswherein the smaller ports or orifices spaced circumferentially to therear of a larger main port with respect to the direction of rotation ofthe valve when the motor is operating and utilizing the orifice effectin relation to motor speed to make substantial use of the expansivepower inherent in the compressed gas.

These and other objects and advantages of this invention will becomemore readily apparent upon consideration of the following descriptionand drawings in which: with a rotary valve constructed according to therinciples FIGURE 1 is a fragmentary sectional view of a portion of amultiple cylinder compressed air motor provided of this invention;

FIGURE 2 is an end elevation partially sectional view of the compressedair motor of FIGURE 1;

FIGURE 3 is a sectional view of a rotary valve constructed according tothe principles of this invention and taken substantially along the line33 of FIGURE 4; and

FIGURE 4 is a transverse sectional view taken substantially along theline 44 of FIGURE 3.

The following description is directed to a preferred embodiment of thisinvention as applied to a particular compressed air motor but should notbe taken as limiting the application of this invention to a motor havinga particular number of cylinders or a specific arrangement of suchcylinders. The valve of this invention is also applicable to motorsoperated by com-pressed gases other than air.

In FIGURE 2 there is shown a five cylinder radial compressed air motor10 of a type well known in the art provided with a suitable single throwcrankshaft 12 (see FIGURE 1) suitable journalled in a suitable crankcaseand having a master bearing 14 rotatably mounted on the single throw 17thereof and suitably connected to a connecting rod 16 for each of thefive cylinders, respectively. Each connecting rod 16 controls the motionof a piston 18 to provide reciprocating motion thereto within a cylinderbore 20 in a manner common to radial engines and motors as is wellknown. Each cylinder bore 20 communicates with an inlet and outlet fluidconducting passageway 22 which in turn communicates with a substantiallycylindrical, hollow manifold body 24 coaxial with the crankshaft 12 andhaving a hollow cylindrical, stationary valve body 26 rigidly securedwithin the manifold body 24, which valve body 26 has an opening 28substantially mating with each passageway 22 to establish communicationbetween passageway 22 and the interior of a generally cylindrical valvemember 30 rigidly secured to one end of the crankshaft 12 for coaxialrotation therewith. With the valve in the position shown in FIGURE 1 agenerally rectangular main port 32 mates with the opening 28 andestablishes communication between the passageway 22 and the interiorpassageway 33 of the valve member 30 which in turn communicates with aninlet channel 34 extending circumferentially around the valve member 30and communicating with a passageway 36 in the valve body 26. Thepassageway 36 in turn communicates with a passageway 37 in an inlet body38 provided with a threaded pipe connection to which is secured fluidconducting means such as a pipe or hose (not shown) connected throughsuitable control devices to a source of compressed air (also not shown).Thus when the piston 18 of a particu lar cylinder is at the top of itsstroke communication is established from the source of compressed airthrough the control device (not shown) to the inlet body 38 through thepassageway 37, the inlet opening 36, the inlet channel 34, thepassageway 33, the main port 32, the opening 28 and the passageway 22 tothe top of the cylinder bore 20 above the piston 18. At the same timecommunication with the other cylinders is established throughpassageways similar to passageway 22 and openings similar to the opening28 but associated with other cylinders to a main exhaust port 40 into anexhaust channel 42 which communicates with an axial exhaust opening 44which in turn communicates with a central opening 46 such as a threadedaxial bore in a flanged generally cylindrical end cap 48 shown as beingcoaxial with the valve body 26 and rigidly secured to the manifold body24 as by elongated cap screws 50. The cap screws 50 extend through aflange portion of the end cap 48, through the inlet body 38 and arethreadedly secured in the manifold body 24 to maintain these parts inrigid, fluid tight, relationship with each other and with the valve body26 during operation of the motor 10. The end cap 48 is provided withsuitable fluid conducting pipe or hose (not shown) connecting with anysuitable sound reducing exhaust system or left open to the ambientatmosphere as desired.

It is to be noted that the valve member 30 is suitably journalled insuitable bearings within the valve body 26 for coaxial rotation thereinat crankshaft speed.

As more clearly shown in FIGURES 3 and 4, the valve member 30 isprovided with a plurality of auxiliary inlet ports in addition to themain port 32. When the valve member 30 is provided-for clockwiserotation as viewed in FIGURE 4, the auxiliary ports arecircumferentially spaced along the periphery of the valve body 30 in acounterclockwise direction with the first and largest of the auxiliaryports indicated as 54, the intermediate port in size and location beingindicated as 56 and the smallest port most distant from the main port 32being indicated as 58. In the embodiment being described the main inletport 32 is a substantially rectangular opening having an axial dimensionof approximately 1%" and an angular dimension of approximately 32 or 1"of circumference while the auxiliary ports are radial bores or orificesof approximately A" diameter for port 54, approximately %2" diameter forport 56 and approximately diameter for port 58. The above dimensions arecited only for the purpose of establishing the great difference in sizebetween the main port 32 and the auxiliary ports 54, 56

'64 so that pressure applied and 58. These dimensions, however, can bevaried according to the design of the engine and the conditions underwhich it will operate especially with respect to the amount of highspeed operation and low speed torque which is required in a particularapplication. The spacing of the ports as shown in FIGURE 4 positions thefirst auxiliary port 54 approximately 44 counterclock wise from the mainport 32 while the second auxiliary port 56 is positioned approximately77 counterclockwise from the port 32 and the smallest port 58 ispositioned counterclockwise from port 32 as measured between thecenterlines of all the ports mentioned. Again it should be noted thatthe spacing in a particular design will be dependent upon theapplication for which the valve 30 is intended. The device of thisembodiment as shown in the figures is set up for clockwise rotation asviewed in FIGURE 2 and for purposes of description the cylin der bodyextending vertically upward in FIGURE 2 and shown in detail in FIGURE 1will be referred to as cylii'i der 60 having an axial centerline 60 withthe other {our cylinders identified as cylinders 61, 62, 63 and 64,respec-- tively, proceeding in a clockwise direction from cylinder 60 asviewed in FIGURE 2 and having respective axial centerlines as'63 and 64'(see FIG. 4). It is to be uiider= stood that within each of the fiveabove enumerated cylin= ders a piston 18 is connected by a connectingrod 16 to the master bearing 14 and consequently to the single throw 17of the crankshaft 12 in a manner well known in the art.

Operation of the device of this invention begins with all parts of theair motor 10 at rest in the relative positions shown' in FIGURE 1.Through the control device compressed air is applied to the passageway37 in the inlet body 38 and, communicating through the valve member 30as hereinbefore described, pressure is applied to the top of the piston18 shown in FIG. 1 as standing at top dead center in the bore 20 in thecylinder 60. However, since the piston 18 in the cylinder 60 is at topdead center application of pressure to the top of the piston 18 in thecylinder 60 has no effect to rotate the crankshaft 12. However, sincecylinder 64 is positioned 72 counterclockwise of cylinder 60, the secondauxiliary port 56, trailing the main port 32 by approximately 77 is in aposition to communicate with cylinder 64 through the valve body 26 byway of an opening 28' related to cylinder 64' in the same manner asopening 28 is related to cylinder 60. Due to the positioning of thecylinder 64 in a counterclockwise direction from the cylinder 60, thepiston within the cylinder 64 is in an intermediate por-- tion of itsdownward stroke with the crank throw 17 standing at an angle to thecenterline 64 of the cylinder to the top of the piston in the cylinder64 will be effective to cause rotation of the motor 10 so that the motoris effectively started. When the crankshaft 12 begins to rotate in aclockwise direc tion as viewed in FIGURE 2, the piston 18 in cylinder 60will travel downwardly and the crank throw 17 will assume an angularposition relative to the centerline 60' and the compressed air suppliedto the cylinder 60 will create a downward force on the piston 18translated into torque applied to the crankshaft 12 as is well known.Since the port 32 and the opening 28 have angular dimensions ofapproximately 32 each, cut off of the compressed air supplied throughthe main port 32 will occur at approximately 64 of crank rotation fromfirst opening of port 32 at which time the piston 18 is in anintermediate portion of its downward stroke. The remaining downwardmotion'of the piston makes use of the expansive energy of the compressedair already in the cylinder 60 at the time to cut off. Further rotationof the valve 30 brings the exhaust port 40 into communication with theopening 28 at or near the bottom of the stroke of piston (18 so that aspiston 18 once more rises in the cylinder 60, the air within thecylinder is exhausted through the passageway 22, the opening 28, theexhaust port 40, the exhaust channel 42, the exhaust opening 44 and theend cap 48 to a suitable exhaust system.

It is to be realized that the above described timing of valve 30 withrespect to the motion of piston 18 is only illustrative and notnecessarily the exact timing to be employed in any motor.

At high speed operation the ports 54, 56 and 58 although briefl-y incommunication with the opening 28 have practically no influence on theabove described op eration because of the orifice effect due to theirsmall size, but when the motor is operating at slow speed the followingactions take place. As the port 32 approaches the cut off position withrelation to the opening 28 the first auxiliary port 54 begins tocommunicate with the opening 28 allowing additional compressed air to beadded to the amount already in the cylinder 60 to maintain fullcompressed air pressure for a greater portion of the stroke than thatoutlined above for high speed operation. Continuing the slow speedoperation as first auxiliary port 54 moves out of communication with theopening 28 the second auxiliary port comes into communication therewithso that pressure is at least partially maintained within the cylinder60. Still further rotation of the motor in the clockwise direction movesthe second auxiliary port out of communication with the opening 28, butat this time the third auxiliary port 58 comes into communicationtherewith to at least partially maintain the pressure Within thecylinder 60. Thus, the auxiliary ports operate at low speed to increasethe mean effective pressure of the motor :10 over that of prior artmotors of comparable high speed efliciency.

While the above actions associated with slow speed operation are takingplace within the cylinder 60, cylinders 61, 62, 63 and 64 are seriallysupplied with compressed air in the same manner with the samemaintenance of pressure throughout a large portion of the downstroke ofthe piston and since each piston is effective through nearly one-half aturn of the crankshaft at least three of the pistons will at all timesbe applying torque to the crankshaft and, when the operation is slowenough for the above described maintenance of pressure, a very hightorque will be applied to the crankshaft 12 as is necessary in manyapplications.

It is now possible to more specifically describe the advantages inherentin the device of this invention wherein: the angular size of the mainintake port 32 is designed to give early out off on the downstroke ofthe piston in high speed operation and the auxiliary ports 54, 56 and 58are small enough to prevent any substantial amount of air entering thecylinder after main port cut off when the motor 10 is operating at highspeed, thus giving the advantage of almost complete utilization of theenergy of the compressed air and resulting in a low rate of airconsumption per horsepower developed; for slow speed operation the sizeof the main inlet port 32 and the resultant early out off would preventthe motor 10 from developing high torque necessary for good slow speedoperation and the auxiliary ports 54, 56 and 58 are sized to allow thepassage of enough air to substantially maintain the pressure ofcompressed air within the cylinder during a large part of the stroke ofthe piston; the auxiliary ports 54, 56 and 58 are also useful inproviding for starting of the motor 10 from any position in which it hasbeen stopped which again would not be possible with the main port 32 asthe only source of compressed air for each cylinder. The use of multipleauxiliary ports gives smoothness of operation.

It is to be realized that the above description has been rather closelyrestricted to a particular compressed air motor 10 but that theprinciples of this invention are applicable to other types of motors andto motors having different numbers of cylinders and that the relativesizes of the main port and the trailing ports can be varied according tothe desired relationship between high speed efliciency and low speedtorque.

A preferred embodiment of this invention having been described andillustrated, it is to be realized that variations in the design andstructure of the valve of this invention are envisioned. Therefore, itis respectfully requested that t'his invention be interpreted as broadlyas possible and limited only by the prior art.

I claim:

1. In a compressed gas operated motor: a rotatably mounted crankshaft; ahollow cylindrical rotary inlet and exhaust valve rotatable in timedrelationship to said crankshaft and in a given direction; a plurality ofcylinders; fluid conducting passageways communicating between said valveand said cylinders respectively, a plurality of circumferentially spacedinlet ports in said valve, one of said ports being larger than any otherof said ports by a ratio greater than 20 to 1 and the others of saidports being spaced rearwardly of said one port relative to saiddirection of rotation.

2. In a compressed gas operated motor; a rotatably mounted crankshaft; ahollow cylindrical valve coaxial with and secured to said crankshaft forrotation therewith in a given direction; a plurality of inlet ports insaid rotary valve, one of sad ports being larger than any other of saidports, said inlet ports having respective coplanar radial centerlinesand being circumferentially spaced by the angles between pairs of saidcenterlines being greater than the number of degrees in the angulardimension of said one of said ports, said other ports being spacedrearward-1y of said one of said ports relative to said given direction.

3. A compressed gas operated motor as defined in claim 2 wherein saidone of said ports is larger than any other of said ports by a ratiogreater than 20 to l.

4. In a multi-cylinder compressed gas operated motor having a pluralityof cylinders, a rotatably mounted crankshaft, a hollow cylindricalrotary inlet and exhaust valve rotatable in timed relationship to saidcrankshaft, fluid conducting passageways communicating between saidvalve and said cylinders respectively, the improvement comprising aplurality of inlet ports in said rotary valve, one of said inlet portsbeing larger than any other of said inlet ports, said inlet ports havingcenters on respective radial centerlines and being circumferentiallyspaced by angles between pairs of said centerlines greater than thenumber of degrees in the angular dimension of said one of said ports.

5. In a compressed gas operated motor: a rotatably mounted crankshaft; ahollow cylindrical inlet and exhaust valve coaxial with and secured tosaid crankshaft for rotation therewith in a given forward direction; amain inlet port, at least one intermediate inlet port and a final inletport in said rotary valve, said main port being larger than any other ofsaid inlet ports, said inlet ports having respective coplanar radialcenterlines and being circumferentially spaced, said intermediate portand said final port being spaced rearwardly of said main port relativeto said forward direction, and the one of said intermediate portsimmediately adjacent said main port being spaced from said main port byan angle greater than the angular dimension of said main port, saidangle being measured between the respective centerlines of said mainport and said one intermediate port.

6. A compressed gas operated motor comprising; a motor housing; aplurality of cylinders within said housing; inlet means havingcompressed gas supplied thereto; exhaust means communicating with theambient atmosphere; a fluid conducting passageway communicating witheach of said cylinders; a rotatably mounted crankshaft; a hollowcylindrical valve coaxial with and secured to said crankshaft forrotation therewith in a given direction; a first passageway in saidvalve communicating with said inlet means; a second passageway in saidvalve communicating with said exhaust means; a plurality of inlet portsin said rotary valve intermittently establishing communication betweenrespective ones of said fluid con-

1. IN A COMPRESSED GAS OPERATED MOTOR: A ROTATABLY MOUNTED CRANKSHAFT; AHOLLOW CYLINDRICAL ROTARY INLET AND EXHAUST VALVE ROTATABLE IN TIMEDRELATIONSHIP TO SAID CRANKSHAFT AND IN A GIVEN DIRECTION; A PLURALITY OFCYLINDERS; FLUID CONDUCTING PASSAGEWAYS COMMUNICATING BETWEEN SAID VALVEAND SAID CYLINDERS RESPECTIVELY, A PLURALITY OF CIRCUMFERENTIALLY SPACEDINLET PORTS IN SAID VALVE, ONE OF SAID PORTS BEING LARGER THAN ANY OTHEROF SAID PORTS BY A RATIO GREATER THAN 20 TO 1 AND THE OTHERS OF SAIDPORTS BEING SPACED REARWARDLY OF SAID ONE PORT RELATIVE TO SAIDDIRECTION OF ROTATION.